title: Related antimicrobial resistance genes detected in different bacterial species co-isolated from swine fecal samples.
abstract: A potential factor leading to the spread of antimicrobial resistance (AR) in bacteria is the horizontal transfer of resistance genes between bacteria in animals or their environment. To investigate this, swine fecal samples were collected on-farm and cultured for Escherichia coli, Salmonella enterica, Campylobacter spp., and Enterococcus spp. which are all commonly found in swine. Forty-nine of the samples from which all four bacteria were recovered were selected yielding a total of 196 isolates for analysis. Isolates were tested for antimicrobial susceptibility followed by hybridization to a DNA microarray designed to detect 775 AR-related genes. E. coli and Salmonella isolated from the same fecal sample had the most AR genes in common among the four bacteria. Genes detected encoded resistance to aminoglycosides (aac(3), aadA1, aadB, and strAB), β-lactams (ampC, ampR, and bla(TEM)), chloramphenicols (cat and floR), sulfanillic acid (sul1/sulI), tetracyclines (tet(A), tet(D), tet(C), tet(G), and tet(R)), and trimethoprim (dfrA1 and dfh). Campylobacter coli and Enterococcus isolated from the same sample frequently had tet(O) and aphA-3 genes detected in common. Almost half (47%) of E. coli and Salmonella isolated from the same fecal sample shared resistance genes at a significant level (χ², p < 0.0000001). These data suggest that there may have been horizontal exchange of AR genes between these bacteria or there may be a common source of AR genes in the swine environment for E. coli and Salmonella.
authors.affiliation: Bacterial Epidemiology and Antimicrobial Resistance Research Unit, Richard B. Russell Research Center, Agricultural Research Service, U.S. Department of Agriculture, Athens, Georgia 30605, USA. jonathan.frye@ars.usda.gov
authors.forename: Jonathan G
authors.initials: JG
authors.lastname: Frye
authors.forename: Rebecca L
authors.initials: RL
authors.lastname: Lindsey
authors.forename: Richard J
authors.initials: RJ
authors.lastname: Meinersmann
authors.forename: Mark E
authors.initials: ME
authors.lastname: Berrang
authors.forename: Charlene R
authors.initials: CR
authors.lastname: Jackson
authors.forename: Mark D
authors.initials: MD
authors.lastname: Englen
authors.forename: Jennifer B
authors.initials: JB
authors.lastname: Turpin
authors.forename: Paula J
authors.initials: PJ
authors.lastname: Fedorka-Cray
mesh_terms: D000818:Animals; D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D015373:Bacterial Typing Techniques; D002167:Campylobacter / Q000145:classification / Q000187:drug effects / Q000235:genetics* / Q000302:isolation & purification; D016000:Cluster Analysis; D024881:Drug Resistance, Bacterial / Q000235:genetics; D004755:Enterobacteriaceae / Q000145:classification / Q000187:drug effects / Q000235:genetics* / Q000302:isolation & purification; D016983:Enterococcus / Q000145:classification / Q000187:drug effects / Q000235:genetics* / Q000302:isolation & purification; D004926:Escherichia coli / Q000145:classification / Q000187:drug effects / Q000235:genetics / Q000302:isolation & purification; D005243:Feces / Q000382:microbiology; D022761:Gene Transfer, Horizontal; D005798:Genes, Bacterial; D019450:Genes, MDR; D008826:Microbial Sensitivity Tests; D020411:Oligonucleotide Array Sequence Analysis; D011815:R Factors / Q000235:genetics*; D019779:Salmonella enterica / Q000145:classification / Q000187:drug effects / Q000235:genetics / Q000302:isolation & purification; D034421:Sus scrofa; D014481:United States
chemical_list: D000900:Anti-Bacterial Agents